<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        const params = [
            ['name', 'zhangsan'],
            ['age', '18'],
            ['sex', '男'],
        ];
        const expect = 'name=zhangsan&age=18$sex=男';

        const str = params.reduce(function (prev,current) {
            const tmp = current.join('=');
            return `${prev}${!prev ? '':'&'}${tmp}`;
        },'');
        console.log(str);


        // const res = params
        //     .map(function (item) {
        //         return item.join('=');
        //     })
        //     .join('&');
        // console.log(res);
    </script>
</body>
</html>